diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td b/llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td
@@ -1566,6 +1566,33 @@
 defm : VPatBinaryWVL_VV_VX_WV_WX<riscv_vwsub_vl,  riscv_vwsub_w_vl,  "PseudoVWSUB">;
 defm : VPatBinaryWVL_VV_VX_WV_WX<riscv_vwsubu_vl, riscv_vwsubu_w_vl, "PseudoVWSUBU">;
 
+// shl_vl (ext_vl v, splat 1) is a special case of widening add.
+foreach vtiToWti = AllWidenableIntVectors in {
+  defvar vti = vtiToWti.Vti;
+  defvar wti = vtiToWti.Wti;
+  let Predicates = !listconcat(GetVTypePredicates<vti>.Predicates,
+                               GetVTypePredicates<wti>.Predicates) in {
+    def : Pat<(riscv_shl_vl (wti.Vector (riscv_sext_vl_oneuse
+                              (vti.Vector vti.RegClass:$rs1),
+                              (vti.Mask V0), VLOpFrag)),
+                            (wti.Vector (riscv_vmv_v_x_vl
+                              (wti.Vector undef), 1, VLOpFrag)),
+                              wti.RegClass:$merge, (vti.Mask V0), VLOpFrag),
+              (!cast<Instruction>("PseudoVWADD_VV_"#vti.LMul.MX#"_MASK")
+               wti.RegClass:$merge, vti.RegClass:$rs1, vti.RegClass:$rs1,
+               (vti.Mask V0), GPR:$vl, vti.Log2SEW, TAIL_AGNOSTIC)>;
+    def : Pat<(riscv_shl_vl (wti.Vector (riscv_zext_vl_oneuse
+                              (vti.Vector vti.RegClass:$rs1),
+                              (vti.Mask V0), VLOpFrag)),
+                            (wti.Vector (riscv_vmv_v_x_vl
+                              (wti.Vector undef), 1, VLOpFrag)),
+                              wti.RegClass:$merge, (vti.Mask V0), VLOpFrag),
+              (!cast<Instruction>("PseudoVWADDU_VV_"#vti.LMul.MX#"_MASK")
+               wti.RegClass:$merge, vti.RegClass:$rs1, vti.RegClass:$rs1,
+               (vti.Mask V0), GPR:$vl, vti.Log2SEW, TAIL_AGNOSTIC)>;
+  }
+}
+
 // 11.3. Vector Integer Extension
 defm : VPatExtendVL_V<riscv_zext_vl, "PseudoVZEXT", "VF2",
                       AllFractionableVF2IntVectors>;
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-gather.ll
@@ -1863,10 +1863,8 @@
 define <8 x i16> @mgather_baseidx_v8i16(ptr %base, <8 x i16> %idxs, <8 x i1> %m, <8 x i16> %passthru) {
 ; RV32-LABEL: mgather_baseidx_v8i16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v8
-; RV32-NEXT:    vadd.vv v10, v10, v10
-; RV32-NEXT:    vsetvli zero, zero, e16, m1, ta, mu
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, mu
+; RV32-NEXT:    vwadd.vv v10, v8, v8
 ; RV32-NEXT:    vluxei32.v v9, (a0), v10, v0.t
 ; RV32-NEXT:    vmv.v.v v8, v9
 ; RV32-NEXT:    ret
@@ -7802,10 +7800,8 @@
 define <8 x half> @mgather_baseidx_v8f16(ptr %base, <8 x i16> %idxs, <8 x i1> %m, <8 x half> %passthru) {
 ; RV32-LABEL: mgather_baseidx_v8f16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v8
-; RV32-NEXT:    vadd.vv v10, v10, v10
-; RV32-NEXT:    vsetvli zero, zero, e16, m1, ta, mu
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, mu
+; RV32-NEXT:    vwadd.vv v10, v8, v8
 ; RV32-NEXT:    vluxei32.v v9, (a0), v10, v0.t
 ; RV32-NEXT:    vmv.v.v v8, v9
 ; RV32-NEXT:    ret
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-masked-scatter.ll
@@ -1444,10 +1444,8 @@
 define void @mscatter_baseidx_v8i16(<8 x i16> %val, ptr %base, <8 x i16> %idxs, <8 x i1> %m) {
 ; RV32-LABEL: mscatter_baseidx_v8i16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v9
-; RV32-NEXT:    vadd.vv v10, v10, v10
-; RV32-NEXT:    vsetvli zero, zero, e16, m1, ta, ma
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v9, v9
 ; RV32-NEXT:    vsoxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret
 ;
@@ -6699,10 +6697,8 @@
 define void @mscatter_baseidx_v8f16(<8 x half> %val, ptr %base, <8 x i16> %idxs, <8 x i1> %m) {
 ; RV32-LABEL: mscatter_baseidx_v8f16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v9
-; RV32-NEXT:    vadd.vv v10, v10, v10
-; RV32-NEXT:    vsetvli zero, zero, e16, m1, ta, ma
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v9, v9
 ; RV32-NEXT:    vsoxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret
 ;
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpgather.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpgather.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpgather.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpgather.ll
@@ -555,9 +555,8 @@
 define <8 x i16> @vpgather_baseidx_v8i16(ptr %base, <8 x i16> %idxs, <8 x i1> %m, i32 zeroext %evl) {
 ; RV32-LABEL: vpgather_baseidx_v8i16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v8
-; RV32-NEXT:    vadd.vv v10, v10, v10
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v8, v8
 ; RV32-NEXT:    vsetvli zero, a1, e16, m1, ta, ma
 ; RV32-NEXT:    vluxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret
@@ -1319,9 +1318,8 @@
 define <8 x half> @vpgather_baseidx_v8f16(ptr %base, <8 x i16> %idxs, <8 x i1> %m, i32 zeroext %evl) {
 ; RV32-LABEL: vpgather_baseidx_v8f16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v8
-; RV32-NEXT:    vadd.vv v10, v10, v10
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v8, v8
 ; RV32-NEXT:    vsetvli zero, a1, e16, m1, ta, ma
 ; RV32-NEXT:    vluxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpscatter.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpscatter.ll
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpscatter.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-vpscatter.ll
@@ -400,9 +400,8 @@
 define void @vpscatter_baseidx_v8i16(<8 x i16> %val, ptr %base, <8 x i16> %idxs, <8 x i1> %m, i32 zeroext %evl) {
 ; RV32-LABEL: vpscatter_baseidx_v8i16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v9
-; RV32-NEXT:    vadd.vv v10, v10, v10
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v9, v9
 ; RV32-NEXT:    vsetvli zero, a1, e16, m1, ta, ma
 ; RV32-NEXT:    vsoxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret
@@ -1127,9 +1126,8 @@
 define void @vpscatter_baseidx_v8f16(<8 x half> %val, ptr %base, <8 x i16> %idxs, <8 x i1> %m, i32 zeroext %evl) {
 ; RV32-LABEL: vpscatter_baseidx_v8f16:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
-; RV32-NEXT:    vsext.vf2 v10, v9
-; RV32-NEXT:    vadd.vv v10, v10, v10
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vwadd.vv v10, v9, v9
 ; RV32-NEXT:    vsetvli zero, a1, e16, m1, ta, ma
 ; RV32-NEXT:    vsoxei32.v v8, (a0), v10, v0.t
 ; RV32-NEXT:    ret